This invention relates to the automatic sewing of an elongated fabric workpiece such as childrens' sleepwear, curtains, womens dress, and the like, and in particular to a method and apparatus for sewing continuous slide fastener chain to elongated fabric pieces intended to be joined by the zipper chain.
The invention is an improvement of apparatus shown and claimed in my preceding U.S. Pat. No. 4,497,270, the substance of which is incorporated herein by reference.
As has been described in my preceding patent, it has often been necessary in the sewing of elongated fabric workpieces to provide relatively intricate manual positioning of the fabric in the sewing machine, and to provide accurate alignment of the fabric relative to unit zippers being sewn therein. Prior to the development of the apparatus of my above mentioned U.S. Pat. No. 4,497,270, the sewing of elongated fabric pieces to unit type zippers had required extremely skillful hand sewing operation. The inevitable result of sewing assembly operations requiring a high level of manual dexterity is that the resulting product is non-uniform. As those familiar with the sewing of clothing are aware, the appearance of the final garment is critically dependent upon the skill of the person operating the sewing machine, and manual sewing results in a substantial number of unsatisfactory garments.
In accordance with my prior patent, automatic machine pulling of the fabric pieces through a sewing station, under controlled tension, was successfully accomplished. As a result of the structure therein disclosed, garments having long unit type zippers were successfully produced, with substantially improved uniformity of sewn product. However, the successful utilization of the machine there described requires substantial manual dexterity in the initial assembly of the zipper and fabric to be sewn therewith. While such dexterity is available, nevertheless the desirability of minimizing the requirement for such physical abilities has led to the improved, substantially completely automatic, sewing apparatus of the present invention.
As will be understood from the construction of my prior U.S. Pat. No. 4,497,270, the embodiment there illustrated called for insertion of a unit type zipper (a preassembled zipper comprised of a pair of chains engaged with a slider) in a fixture positioning the tape edge of each of the chains adjacent the edge of the fabric. Upon completion of the sewing operation, the zipper was closed by manipulating the slider, at which point the stitched edges of the fabric were turned under and the zipper became substantially concealed. The manual positioning of the zipper parts and the manual positioning of the fabric in advance of the sewing operation permit possible misalignment and other operator errors unless careful attention is constantly paid to the apparatus during initiation of the sewing operation.